Differences in the pacing patterns of female medallists and nonmedallists in the 400-m freestyle swimming event

Sex differences in pacing patterns are reported in triathlons (Vleck et al., 2008, Journal of Science and Medicine in Sport, 11, 424–432) and 1-mile runs (Foster et al., 2014, International Journal of Sports Physiology and Performance, 9, 715–719) but not in 100- to 1500-m swimming events (Robertson et al., 2009, Journal of Sports Sciences, 27, 387–395). Successful pacing patterns for males, i.e., those leading to a medal winning performance, can be identified using competition data in the 400-m freestyle swim (Mytton et al., 2015, International Journal of Sports Physiology and Performance, 10, 369–373). Given the lack of existing research, the aim of this study was to identify successful pacing patterns in the 400-m freestyle swim for elite females. Following approval from Northumbria University ethics committee, 100-m split times were collected from finals in the 400-m freestyle between 2006 and 2012 including European, World and Commonwealth competitions. Times from 48 performances were converted into normalised lap speed, compared between medallists and non-medallists and relative to the gold medallist. A Kruskal– Wallis test was followed by an estimation of the magnitude of the effect (Cohen’s d). Female medallists display a significantly faster normalised speed in lap 3 (P = 0.030, moderate effect) and lap 4 (P = 0.015, moderate effect) compared to non-medallists but were slower in lap 2 (P = 0.006 moderate effect). When expressed relative to the gold medallist, the lower finishing places swam significantly slower in laps 1, 3 and 4 (P = 0.045, 0.009 and 0.001, respectively) but not compared to second and third places. To win a medal in 400-m swimming, it appears necessary to vary pace by adopting a more conservative pace in the early stages of a race to allow for a relatively greater increase in speed at the end resulting in a U-shaped pattern. The successful female athletes demonstrated this by conserving energy in the second lap thereby preserving capacity for an end-spurt due to a lower prior physiological disturbance. The U-shaped pattern was flatter than observed in male swimmers who reduced speed to a greater extent early on and increased speed more later on (Mytton et al., 2015). More research is needed to understand why this flatter profile exists, for example it could be that females have less confidence to conserve speed early in a race and therefore don’t have the same reserves by the end or the opposite could be true and that over-confidence early on leads to less reserves at the end of the race. Alternatively, females may not be required to increase their speed as much in the latter stages in order to win because the winning margins are greater than in the men’s event.